Search

A combined experimental and molecular dynamic simulation approach was used to examine the structure and interfacial properties of solute-saturated micelles. The properties of dodecylbenzenesulfonate (DBS) micelles were examined in dodecane and benzene hydrocarbon systems. Pyrene fluorescence was used to determine the aggregation number of surfactant monomers in the micelle systems. Molecular dynamic (MD) simulations using energy minimization applying the CHARMm force field with the TIP3P model for water. Comparison of the DBS/benzene and DBS/Dodecane micelles equilibrium structures via radial distribution function (RDF) and probability distribution function (PDF) analysis indicates that the area per head group for the DBS/Benzene micelle interface is significantly larger than that of the DBS/Dodecane at the interface. It was also determined that benzene molecules can move freely within the micelle while dodecane is strictly confined in the core of the micelle. The increased interfacial area per monomer caused by the insertion of benzene also reduces the effectiveness of the surfactant, which has implications for use in various environmental applications. However, the DBS/benzene micelle can solubilize many more hydrocarbon molecules in one micelle with less surfactant monomer (i.e., lower aggregation number) per micelle due to the increased available packing positions within the micelle. This, in turn, increases the efficiency of the surfactant in real-world applications which is consistent with previous laboratory results. Understanding the differing solubilization characteristics of surfactants against various classes of hydrocarbons in single solute systems is a necessary step to beginning to understand their solubilization properties in the mixed waste systems prevalent in most surfactant enhanced remediation (SEAR) strategies. [ABSTRACT FROM AUTHOR]

The paper proposes a method that analyses the dynamic damage probability of laser systems to address the shortcomings of the quantitative model for the damage probability of laser systems. Firstly, the far-field energy density distribution model is constructed according to the power spectrum inversion method. Then, the instantaneous on-target spot power density distribution is equivalently portrayed based on the combination of the far-field power density and the missile target characteristics. Next, the instantaneous on-target spot is combined with the tracking and aiming error to obtain the probability distribution of the energy density of the long-period on-target spot. Finally, the temperature probability distribution is obtained by analyzing the relation between the target energy density and the temperature of the inner wall of the warhead. Consequently, the damage probability was calculated. The simulation shows that there is a unique maximum damage probability when the target is flying in a straight line and the laser system strikes the missile sideways. The method can provide support for the shooting timing of high-energy laser systems. [ABSTRACT FROM AUTHOR]

This paper presents a study on the relationship between transport properties and geometric free volume for a hard sphere (HS) system in a dense fluid region. First, a generic free volume distribution function is proposed based on recent simulation results on the HS geometric free volume by Maiti and Sastry [J. Chem. Phys. 141(4), 044510 (2014)] and Maiti et al. [Eur. Phys. J. E 36(1), 5 (2013)]. Combining the new distribution function with a local particle transportation model, we obtain a power law for the HS transport properties. Then, a relation between the geometric free volume and thermodynamic free volume is established, which makes it possible to use well-developed equations of state (EoS) for the expressions of the geometric free volume. The new power law models are tested with molecular dynamic simulation results for HS viscosity, diffusivity and thermal conductivity, respectively, and the results are very satisfactory. Moreover, using the power law, we are able to reproduce several equations obtained from different approaches, such as the entropy scaling laws [Bell et al., J. Phys. Chem. B 123(29), 6345–6363 (2019]), mode coupling theory [Barrat et al., J. Phys. Condens. Matter 1, 7163–7170 (1989)], or empirical correlations [Sigurgeirsson and Heyes, J. Mol. Phys. 101(3), 469–482 (2003)]. In particular, a long-standing controversy regarding the well-known Cohen–Turnbull–Doolittle free volume model [Cohen and Turnbull, J. Chem. Phys. 31(3), 1164–1169 (1959); Doolittle, J. Appl. Phys. 22(12), 1471–1475 (1951)] is resolved by using the power law combined with the Heyes and Woodcock EoS [Heyes and Woodcock, Mol. Phys. 59(6), 1369–1388 (1986)]. [ABSTRACT FROM AUTHOR]

Thermal conductivities of polybutadiene crosslinked with sulfur as a function of the heat flux autocorrelation function by using an equilibrium molecular dynamic (EMD) simulation were investigated. The Green–Kubo method was used to calculate thermal conductivities. All simulations were performed by applying the LAMMPS software (version 3 Mar 2020) package. The united-atom force field (OPLS-UA) from the Moltemplate software (version 2.20.3) was applied in the simulations. The influence of uniform and random distributions of sulfur in polybutadiene on the final value of thermal conductivities was studied by polymeric model structures with similar and variable degrees of crosslinking. The results showed that for identical degrees of crosslinking, the distribution of crosslinkers in the polymeric model structures significantly influenced the final value of thermal conductivity. Moreover, the influence of the crosslinking degree on the final value of thermal conductivity was studied by considering polymeric model structures with different degrees of crosslinking. The results demonstrate that by having a random distribution of sulfur, the thermal conductivity will be enhanced. However, by increasing the degree of crosslinking to the higher percentage in random crosslinked model structures, the value of thermal conductivity drops significantly due to possible higher crystallization of the model structures, which decrease the degree of freedom for phonon contributions. [ABSTRACT FROM AUTHOR]

The rigid-flexible coupling cable system under large deformation is studied, and the beam element from absolute node coordinate formulation is used to establish flexible cable body of the system. Different numerical integral algorithms are discussed for solving the rigid-flexible cable system and an integration strategy which combines Implicit Euler with Minimum Residual Method (MINRES) is proposed. The influence of the position and number of rigid components and different the lengths of the flexible elements on the system dynamics are analyzed. With constant total mass of the system, higher number of rigid components and their uniform distribution contribute to stabilization of the swing of the flexible cable body. When the total length of the cable is constant, increasing the number of beam elements enhances the nonlinear characteristics of the swing motion and damages the stability. The influence of different factors on the movement of large deformation flexible cable body is obtained through modeling and simulation of the rigid-flexible coupling cable system. [ABSTRACT FROM AUTHOR]

The Alhué mining district, Chile, is an example of a high-grade Au-Ag-Zn(-Pb) deposit with mineralized veins that contain variable amounts of copper sulfides, which are detrimental to the cyanidation process. Similar deposits can be found in the central zone of Chile, with polymetallic veins (Au, Ag, Cu, Pb, and Zn) that are related to subvolcanic intrusive events, the development of collapse calderas, and extensive hydrothermal alteration, such as Bronces de Petorca, the Chancón mining district and Cerro Cantillana; areas of the world with similar formations include the western United States and the Henan Province in central China, for example. Mineralogical variation can be managed within the metallurgical process by alternating its operational modes. The decision to switch between modes is governed by current and forecasted stockpile levels feeding into the process, according to a discrete rate simulation (DRS) framework that has now been developed to incorporate head grade data for gold. Customized simulations that incorporate probability distribution models using head grade have now been developed, following a statistical analysis based on data from the Alhué district. This study applies data-driven simulation modeling to represent standardized operational modes and their impact on the operational performance of gold extraction. [ABSTRACT FROM AUTHOR]

In rolls manufactured from first bent and then welded sheets of steel, the asymmetric distribution of mass due to the weld seam as well as imperfections of the geometry due to the bending may cause the roll cross-section roundness profiles to deform due to centrifugal forces when the roll is accelerated to rotate at its operating speed. This effect is known as the dynamic geometry of the roll. In previous research, it has been shown that it is possible to measure the dynamic geometry in operating speed and compensate for the deformation by grinding a suitable opposite geometry on the roll. This direct approach may work when only little material is removed. Such conditions apply especially for polymer coated rolls, where the dynamic geometry is mostly dependent on the geometry of the much stronger and denser steel body under the roll cover. This paper goes further to investigate the possibilities for compensating the dynamic geometry in cases where the amount of removed material is significant enough to have an effect on the dynamic geometry itself due to altered mass and stiffness. The paper presents a toolchain consisting of a parametric roll CAD model, finite element simulation of the dynamic geometry and a geometry optimization procedure based on minimizing a target function describing roundness errors in cross-sections of the roll. Results of simulation experiments for a case example indicate that the presented optimization procedure can be used to eliminate roundness errors related to dynamic geometry of the roll. Finally, the paper discusses the application of such a toolchain in the manufacturing of rolls. [ABSTRACT FROM AUTHOR]

A uniform distribution of power density (energy flux) in a stationary laser beam leads to a decrease in the overheating of the material in the center of the laser beam spot during laser powder bed fusion and a decrease in material losses due to its thermal ablation and chemical decomposition. The profile of the uniform cylindrical (flat-top) distribution of the laser beam power density was compared to the classical Gaussian mode (TEM00) and inverse Gaussian (donut) distribution (airy distribution of the first harmonic, TEM01* = TEM01 + TEM10). Calculation of the Péclet number, which is a similarity criterion characterizing the relationship between convective and molecular processes of heat transfer (convection to diffusion) in a material flow in the liquid phase, shows that the cylindrical (flat-top) distribution (TEM01* + TEM00 mode) is effective in a narrow temperature range. TEM00 shows the most effective result for a wide range of temperatures, and TEM01* is an intermediate in which evaporation losses decrease by more than 2.5 times, and it increases the absolute laser bandwidth when the relative bandwidth decreases by 24%. [ABSTRACT FROM AUTHOR]

• Binary silica-germania glasses studied using MD simulations. Structural models validate by comparing with experiments. • Ge4+ has four-fold coordination with Ge-O bond distance of 1.71 Å. Mixed glasses form a continuous random network with SiO 4 and GeO 4 tetrahedra. • GeO 4 units are slightly more distorted than SiO 4. Ge-O-Ge forms a lower angle and broader distribution in comparison with Si-O-Si. • Nearly perfect random distribution of SiO 4 and GeO 4 was achieved over all the mixing extent. • Ring size distribution analysis showed the population smaller rings is slightly higher in GeO 2 containing glasses. This study explores the structural properties of mixed silica-germania glasses, which find wide applications in microelectronics and optoelectronics, by using molecular dynamics (MD) simulations. After validating the germanium related potential parameters, the short and medium-range structural features across the binary glass range were investigated. The results show that Ge-O bond distance is 1.71 Å and germanium maintains four-fold coordination in all the glasses. The [GeO 4 ] tetrahedrons are slightly more distorted as compared to silica while the intertetrahedral angle distributions become narrower with increasing GeO 2. GeO 2 -rich glasses exhibit broader ring size distributions. [SiO 4 ] and [GeO 4 ] tetrahedrons are randomly mixed forming a continuous random network. Comparison of the simulated glass structures with results from experiments such as neutron diffraction, solid state NMR and Raman spectroscopy showed good agreements, validating the structural model from MD simulations. This paves the way for future studies of composition dependence of properties of these mixed former glasses. [ABSTRACT FROM AUTHOR]

• Novel CRB vibration model considering contact stiffness and natural frequency characteristics. • The outer raceway spalling fault with varying sizes is simulated in this paper, considering spalling defect extents and load distribution. • This paper showed that the effects of contact stiffness variation on natural frequency characteristics by the statistical distribution of fault feature signals. The modeling of early spalling defects in cylindrical roller bearings (CRB) is a challenging problem in fault diagnosis. Due to the absence of prominent "drop-in" excitation, accurately describing the signal characteristics of the early failure mechanism model for CRBs becomes difficult. In this paper, the failure of cylindrical roller bearings due to spalling caused by fatigue is a frequent occurrence. The previous defect models have been centered on sharp-edge impact between the roller and spalling defects. However, they have not provided an adequate depiction of the variation in contact stiffness caused by roller-fault interaction. In this paper, a novel CRB vibration model that takes into account contact stiffness and natural frequency characteristics is proposed. The model considers both the load redistribution and contact stiffness variation caused by spalling defects. This new model provides a spring-damper system based on contact stiffness between the roller and raceway, enabling an estimation of the CRB system's natural frequency characteristics. The outer raceway spalling fault with varying sizes is simulated in this paper, taking into account spalling defect extents and load distribution. The vibration response of the fault signal model is investigated. The simulation results show that the load and contact stiffness will change as the roller passes through the defect zone. Furthermore, the statistical distribution of fault feature signals demonstrates the effects of contact stiffness variation on natural frequency characteristics. The experiments given in this paper have verified the simulation results of the proposed signal model. [ABSTRACT FROM AUTHOR]

• To reduce the occurrence of alarm floods, improved rationalization strategies are introduced to evaluate the quality and effectiveness of multivariate alarm systems developed in recent research. • Strategies demonstrated on an exothermic CSTR result in a significant reduction in nuisance alarms. • Real-time risk of the rationalized alarm systems were evaluated using dynamic risk assessment by estimating their failure probabilities using multiple dynamic simulations. • The posterior distribution, constructed for the exothermic CSTR using Bayesian statistics, had much lower variance as compared to one developed using a flat prior. In this paper, improved alarm rationalization strategies are introduced to evaluate the quality of the multivariate alarm systems developed in previous work – with the alarm thresholds and response actions modified appropriately, based on key statistical metrics. For an exothermic CSTR, our strategies resulted in a significant reduction in the number of nuisance alarms, focusing on only quality alarms, which, if ignored, are more likely to result in an abnormal shift in operation to the undesirable regions. Next, their real-time performance is evaluated using dynamic risk analysis (DRAn), in which, the associated risk is analyzed by estimating the failure probabilities of the multivariate alarm systems using Bayesian statistics, based on multiple dynamic simulations for the process, inclusive of control, alarms and response actions. As expected, the failure probability distribution developed for the exothermic CSTR has a much lower variance as compared to one developed using a flat prior distribution. [ABSTRACT FROM AUTHOR]

• A CA-based model of slope soil erosion was constructed to simulate complex spatiotemporal dynamic behaviors and processes. • A simulation model was developed for the transition between various types of soil erosion intensity. • To predict the development trend of soil erosion in different regions under different rainfall conditions. • Based on transition probability matrix and suitability map, the future trend of slope soil erosion intensity was simulated. The study of soil erosion is significant to soil and water conservation and ecological construction planning. CA, a dynamic modeling method, has been widely used to simulate the future changes of soil erosion intensity. In this study, three slopes with different vegetation patterns (uniform distribution, aggregated distribution, and random distribution) and a bare slope in the Baojiagou watershed in the Pisha sandstone area were taken as the study objects. Based on the soil erosion intensity grade maps of slopes with different vegetation patterns under the three periods of rainfall, the soil erosion intensity grade maps of the four slopes were simulated by combining multi-criteria evaluation (MCE) and Markov chain (CA-Markov). Through tests, the Kappa coefficients of the simulated maps of uniform distribution, random distribution, aggregated distribution and a bare slope reached 80.15%, 75.41%, 75.92% and 76.48%, respectively. The results revealed that the soil erosion types on slopes with different vegetation patterns were transferred differently, and fewer erosion areas were generally transferred into highly eroded ones, with moderately and slightly eroded areas as the main transfer flows. After simulating the grade map of soil erosion intensity on slopes with different vegetation patterns, it was found that the slopes with uniform and random vegetation distribution primary displayed the transfer from highly eroded areas to less eroded ones, and the sedimentary area was enlarged, while the slope with aggregated vegetation distribution and the bare slope mainly presented the transfer from less eroded areas to highly eroded ones. The sedimentary area was diminished. Therefore, compared with the bare slope, the slopes with uniform and random vegetation distribution exerted a better inhibitory effect on the soil erosion degree of hydraulically eroded slopes, and the inhibitory effect of aggregated vegetation distribution-type slope was the weakest. The study results provide critical information for planning and implementing soil conservation measures in the study area. [ABSTRACT FROM AUTHOR]

Multiple failuremodes and strength degradation are usually inherent in the gear transmission system, which brings new challenges for conducting fatigue reliability analysis and design. This paper proposes a novel dynamic fatigue reliability analysis method for failure dependence and strength degradation based on the combination of theCopula function and Gamma process. Firstly, the dynamic simulation model of the gear transmission system is established to obtain the dynamic stress-time history. The Gamma process is then used to describe the strength degradation to establish the dynamic stress-strength interference model. The marginal distribution functions of tooth contact fatigue and dedendumbending fatigue are calculated respectively based on the dynamic interferencemodel. Finally, the joint distribution of the two failure modes can be obtained by the t-Copula function to characterize the failure dependence, and so the dynamic fatigue reliability considering failure dependence can be estimated. The effectiveness of the proposed method is illustrated with examples. The results reveal the temporal law of reliability and the effects of failure dependence on dynamic fatigue reliability. [ABSTRACT FROM AUTHOR]

We characterize the Gaia –Enceladus–Sausage kinematic structure recently discovered in the Galactic halo using photometric metallicities from the SkyMapper survey, and kinematics from Gaia  radial velocities measurements. By examining the metallicity distribution functions (MDFs) of stars binned in kinematic/action spaces, we find that the |$\sqrt{J_R}$| versus Lz space allows for the cleanest selection of Gaia –Enceladus–Sausage stars with minimal contamination from disc or halo stars formed in situ or in other past mergers. Stars with |$30 \le \sqrt{J_R} \le 50$| (kpc km s−1)1/2 and −500 ≤ Lz  ≤ 500 kpc km s−1 have a narrow MDF centred at [Fe/H] = −1.17 dex with a dispersion of 0.34 dex. This [Fe/H] estimate is more metal-rich than literature estimates by 0.1−0.3 dex. Based on the MDFs, we find that selection of Gaia –Enceladus–Sausage stars in other kinematic/action spaces without additional population information leads to contaminated samples. The clean Gaia –Enceladus–Sausage sample selected according to our criteria is slightly retrograde and lies along the blue sequence of the high V T halo colour magnitude diagram dual sequence. Using a galaxy mass–metallicity relation derived from cosmological simulations and assuming a mean stellar age of 10 Gyr, we estimate the mass of the Gaia –Enceladus–Sausage progenitor satellite to be 108.85–9.85 M⊙, which is consistent with literature estimates based on disc dynamic and simulations. Additional information on detailed abundances and ages would be needed for a more sophisticated selection of purely Gaia –Enceladus–Sausage stars. [ABSTRACT FROM AUTHOR]

Highlights • A Gaussian process based model is constructed to simulate a complex biological system. • Model accuracy and predictive capability is compared against the neural network model. • Dynamic optimisation under uncertainty is conducted to maximise algal lutein production. • A framework to build bioprocess models with Gaussian Processes is presented. Abstract Dynamic modeling is an important tool to gain better understanding of complex bioprocesses and to determine optimal operating conditions for process control. Currently, two modeling methodologies have been applied to biosystems: kinetic modeling, which necessitates deep mechanistic knowledge, and artificial neural networks (ANN), which in most cases cannot incorporate process uncertainty. The goal of this study is to introduce an alternative modeling strategy, namely Gaussian processes (GP), which incorporates uncertainty but does not require complicated kinetic information. To test the performance of this strategy, GPs were applied to model microalgae growth and lutein production based on existing experimental datasets and compared against the results of previous ANNs. Furthermore, a dynamic optimization under uncertainty is performed, avoiding over-optimistic optimization outside of the model's validity. The results show that GPs possess comparable prediction capabilities to ANNs for long-term dynamic bioprocess modeling, while accounting for model uncertainty. This strongly suggests their potential applications in bioprocess systems engineering. [ABSTRACT FROM AUTHOR]

This paper presents a model that incorporates the impact of islanding dynamics in reliability evaluation of active distribution networks. In order to do that, the effects of the islanding process in terms of voltage and frequency variations, as well as the impact of component failures, are taken into consideration in the reliability assessment. The proposed model is based on a combination of probabilistic reliability evaluation with the dynamic simulation of the islanding process. The reliability evaluation is performed by Non-Sequential Monte Carlo simulation, while the islanding process is evaluated by a transient stability simulation with complete models of synchronous machine and its voltage and speed regulators. Results are obtained for a MV distribution test system, where the influence of dynamics in the survivability rate of islanding is incorporated into the calculation of traditional reliability indices, leading to more realistic results. [ABSTRACT FROM AUTHOR]

• European-scalable method to simulate rainfall erosivity from gridded rainfall data. • Monthly power-law models link rainfall depth to erosivity with European coverage. • EMO-5 shows the best potential to simulate rainfall erosivity events. • Gridded datasets perform better in Northern over Southern Europe. • Future upscaling and regional bias correction may overcome current limitations. Soil erosion is time compressed into a number of episodic erosive rainfall events with an associated potential to detach and transport soil particles (rainfall erosivity), each possessing unique spatial and temporal characteristics. Rainfall erosivity events in Europe follow extreme value distributions in which a limited number of rainstorms dominate the long-term budget of available erosive energy. To combat soil erosion in Europe in a targeted manor, timely erosion mitigation measures should derive from dynamic model simulations that incorporate spatially and temporally distributed estimations of rainfall erosivity. Rain gauge measurements from singular points are typically used to quantify rainfall erosivity, however the spatial uniqueness of rainfall presents a key limitation to dynamically model rainfall across broad spatial scales with a limited number of point measurements. Discretised gridded precipitation datasets with a widespread (e.g. continental) spatial coverage potentially offer an opportunity to adequately replicate the dynamics of rainfall erosivity events, however their performance remains poorly tested in the pan-European context. This study builds upon the comprehensive Rainfall Erosivity Database at European Scale (REDES) archive of over 300,000 events from 1181 gauge stations to develop a two-step modelling process: 1) firstly, optimal monthly models were fitted and evaluated between gauge-recorded rainfall depth and rainfall erosivity (EI 30) across European climatic regions to develop a European-scale parameter surface, 2) secondly, three datasets (EMO-5 (6-hr), E-OBS (24-hr), UERRA MESCAN-SURFEX (24hr)) were directly evaluated via a grid-to-point analysis based on their ability to simulate the station-specific event rainfall erosivity timeseries at a random selection of 32 locations. EMO-5 (Nash-Sutcliffe model efficiency mean = 0.24) outperformed other tested gridded datasets, showing the capability to adequately replicate the event number, timing, and their average magnitude. A higher model performance in Northern compared with Southern European climatic regions, in which characteristically higher and spatially-complex event rainfall erosivity magnitudes are found, was symptomatic of a poor ability of grid-based simulations to replicate the magnitudes of events in the outer extents of the frequency-magnitude spectrum. The absence of a clear global systematic predictive bias amongst simulated locations suggests the need for future upscaling of this analysis to the entire European REDES dataset to fully understand and correct for the method-derived bias in a climate region-specific way. [ABSTRACT FROM AUTHOR]

Abstract: This paper contributes to research on “postponement” strategy in the context of a global production–distribution system of an automobile manufacturer. It proposes a model that integrates multiple considerations germane to global supply chains. Postponement is important in this context because it is necessary to consider international transfers and tariffs, and it is important to appropriately account for the impact of postponement on total costs. Consideration of several key variables such as shipping point, customs tariff, and cost differences between countries is essential to derive full benefits from postponement strategy in global supply chains. International transfer of goods among countries in global automobile industry is complex and dynamic because of the multitude of factors that must be considered. The paper develops insights regarding postponement strategy in global supply chains via a system dynamics simulation model. The model draws on the experiences of a Korean automobile manufacturer with operations in developing and developed countries. The results of the system dynamics simulations show that the choice of optimal shipping point and the right level of postponement under the “decoupling points” strategy in global operations has a significant effect on overall cost efficiency, when decoupling point and postponement timing are considered simultaneously. The results also show that there are key differences in executing the postponement strategy when shipping to a developing country as opposed to a developed country. This insight has practical implications for global operations and is helpful in developing a sophisticated framework for executing the postponement strategy as manufacturing firms expand their operations globally. [Copyright &y& Elsevier]

Abstract: Discrete-particle simulations of a gas–solid fluidized bed are used to investigate the species segregation (de-mixing) behavior of systems with continuous particle size distributions. Both Gaussian and lognormal distributions are investigated over a range of distribution widths, restitution and friction coefficients, and gas velocities. The results indicate that: (i) the average particle diameter decreases as the height within the bed increases, (ii) the level of segregation increases with an increase in the width of the particle size distribution, and (iii) segregation is attenuated as bubbling becomes more vigorous. Furthermore, the shape of the local size distribution (i.e., Gaussian or lognormal) is found to mimic that of the overall size distribution in most regions of the fluidized bed. [Copyright &y& Elsevier]

• Extension of recent frequency stability works to separation events in power systems. • The multi-area model co-optimises energy, frequency response resources and inertia. • DC-OPF model minimises the operation costs of a system that faces risk of splitting. • Results of the resilience-oriented model are validated using dynamic simulations. • The model has been designed to be compatible with dispatch engines used by ISOs. Weakly interconnected power systems face separation risk during extreme weather events or due to cascading failures. These contingencies may become particularly severe in low-inertia grids, where the sub-regions resulting after system split need to procure enough resources to respond to low (importing areas) and high (exporting areas) frequency conditions. This paper introduces a separation event-constrained optimal power flow (SECOPF) with considerations of inertia and frequency response resources allocation in each balancing area to be capable to withstand, besides the largest generation and load contingencies, also the loss of selected interconnectors. The model, cast as mixed integer linear program, is tested on a reduced version of the Australian power system and validated via dynamic simulation. The results show how the system's frequency resilience to extreme events can be effectively enhanced for both high- and low-frequency conditions that arise in different areas after an interconnector's trip. This is achieved by co-optimising the interconnector flow magnitudes along with the distribution of frequency response resources and inertia levels in each area. [ABSTRACT FROM AUTHOR]

• The simulated Fe-rich slag structure fits well with the experimental data. • Fe is predominately 4- and 5-fold coordinated with O. • The [FeO 4 ] units are connected by sharing corners while the [FeO 5 ] polyhedra share edges. • Fe and Ca seem to be randomly distributed throughout the silicate network. Non-ferrous metallurgy slags are gaining significant interest as a resource in the production of alternative low-energy cementitious materials. Their atomistic structures, however, are still not fully understood due to their glassy nature. In the work presented herein, a comprehensive description of the nano-structure of a CaO-FeO-SiO 2 slag was obtained by using molecular dynamic simulations in conjunction with previously obtained experimental data from X-ray and neutron pair distribution function studies. Iron was predominately 4- and 5-fold coordinated with oxygen, forming polyhedra in tetrahedral and pyramidal/triangular bipyramidal configuration. The [FeO x ] polyhedra were corner-shared to the silica tetrahedra, while the higher coordinated fractions (x = 5 or 6) seemed to prefer to be next to each other, sharing edges. Ca was mostly surrounded by 6 or 7 oxygens in polyhedra that are predominantly edge-sharing with other units. The obtained results fit the experimental data well and as such provide an accurate and realistic picture of the iron-rich slag structure. [ABSTRACT FROM AUTHOR]